Narrative:

Another aircraft received IFR clearance before my aircraft and this pilot had not started engines. Trying to stay on schedule, I decided to depart VFR and get IFR airborne. Center would not give IFR clearance because of aircraft on ground with IFR clearance. As we continued to west, ceiling lowered and aircraft departed behind us. To maintain separation, I told center I would stay at 4500 ft, other aircraft would climb to higher altitude before we could get IFR clearance. Both aircraft on radar. Ceiling lowered to the west and after 15 plus mi I was IMC on a VFR flight. I should have waited for aircraft to depart. WX at depart/arrival airports does not guarantee WX en route.

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Original NASA ASRS Text

Title: FLC OF AN LTT FLEW INTO IMC ON A VFR FLT PLAN.

Narrative: ANOTHER ACFT RECEIVED IFR CLRNC BEFORE MY ACFT AND THIS PLT HAD NOT STARTED ENGS. TRYING TO STAY ON SCHEDULE, I DECIDED TO DEPART VFR AND GET IFR AIRBORNE. CTR WOULD NOT GIVE IFR CLRNC BECAUSE OF ACFT ON GND WITH IFR CLRNC. AS WE CONTINUED TO W, CEILING LOWERED AND ACFT DEPARTED BEHIND US. TO MAINTAIN SEPARATION, I TOLD CTR I WOULD STAY AT 4500 FT, OTHER ACFT WOULD CLB TO HIGHER ALT BEFORE WE COULD GET IFR CLRNC. BOTH ACFT ON RADAR. CEILING LOWERED TO THE W AND AFTER 15 PLUS MI I WAS IMC ON A VFR FLT. I SHOULD HAVE WAITED FOR ACFT TO DEPART. WX AT DEPART/ARR ARPTS DOES NOT GUARANTEE WX ENRTE.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.